Method for making a heat dissipator



Sept 3, 1968 J. H. J-AcoBY 3,399,444

METHOD FOR MAKING A HEAT DISSIPATOR Original Filed May 8, 1963 Fvg. 5.

I mlnll Fig/1.

INVENTOR. JOHN H-J'ACOBY United States Patent 3,399,444 METHOD FOR MAKING A HEAT DISSIPATOR John H. Jacoby, 53 Bartlett St., Chelmsford, Mass. 01824 Original application May 8, 1963, Ser. No. 278,859. Divided and this application Oct. 18, 1965, Ser. No. 510,423

2 Claims. (Cl. 29157.3)

ABSTRACT OF THE DISCLOSURE A method for making a heat dissipating device or radiator which conducts heat away from a heat source through protuberances such as parallel, spaced-apart wire pins. The manufacturing method consists of driving staple-like Wire elements into a temporary support or retainer sheet, applying bonding agent to the element bases, positioning a metal sheet against the element bases, applying heat to achieve a metallurgical bond and removing the support sheet.

This is a division of application Ser. No. 278,859, filed May 8, 1963.

This invention relates to an improved heat dissipator especially for use in electronic assemblies and to an improved method for making such heat radiators.

Heat dissipators of this character are usually called heat sinks but may be called cooling units, temperature modifiers or the like. In many fields, it is well known to provide heat dissipators for conducting heat away from a heat source and dissipating the heat by radiation from roughened surfaces, integral protuberances such as fins, rods, pins, or anges or by multiple tubular flow conduits. However, space, size and weight limitations, as well as cost factors, have made it difficult to use such heat exchange elements in electronic assemblies for encircling an electron tube or supporting transistors.

The principal object of this invention is to provide a method for making a heat dissipator having a bristle-like, or pin fin surface formed by a multiplicity of heat conductive, spaced, self supporting pins covering one face of a heat conductive, self supporting body, the pins dissipating heat and the dissipator being shaped to conform to the shape of the heat source.

Another object of the invention of the invention is to provide a method for making a heat dissipator of readily deformable material so that it can be made in at condition and then bent into the desired iinal shape, for example into a hollow cylinder or helix for enclosing an electron discharge tube.

A further object of the invention is to provide a method for making a hollow, cylindrical heat sink having inwardly projecting heat conductive, deformable, resilient pins, the pins defining a cyclinder of less diameter than the exterior diameter of a tube. Thus the heat sink may be axially slid down around a tube and secured to the chassis, while the pins are uniformly bent into angular relation to the tube envelope, thereby providing an impact cushion, or shock mount, as well as a heat transfer device.

Still another object of the invention is to provide a simple, low cost method for making heat sinks from heat conductive wire and sheet material wherein Wi-re pin bodies are metallurgically bonded normal to one face of a relatively large sheet or web, the sheet or web is then slit into 3,399,444 Patented Sept. 3, 1968 the desired area to form blanks, and the blanks are then bent into heat sinks of the required configuration.

A still further object of the invention is to provide a method for making an improved assembly of an electron discharge tube and a heat sink, the heat sink being a hollow cylindrical body with radial pins projecting inwardly therefrom, the pins engaging the tube envelope for supporting the heat sink thereon while conducting heat away from the envelope.

Other objects and advantages of the invention will be apparent from the claims, the description of the drawing and from the drawing in which:

FIGS. l to 3 are diagrammatic, sectional side elevations showings one method of making a sheet of heat dissipator material in accordance with the invention.

FIGS. 4 to 6 are similar diagrammatic views showing another method for making the heat dissipator material.

FIG. 7 is a diagrammatic perspective view showing the slitting of the material into blanks of the desired area.

FIG. 8 is a diagrammmatic side elevation, in section, showing the heat dissipator of F IG. 7 formed into cylindrical and helical configurations.

FIG. 9 is a perspective view showing a heat dissipator of the invention enclosing, and supported by, a tube.

FIG. 10 is a side elevation, partly in section, showing a heat dissipator of the invention secured to a chassis and and serving as a shock mount.

FIG. 11 is a side elevation, partly in section, of a narrow strip of a heat dissipator material wound as a helix to enclose a tube.

FIG. 12 is an end elevation, partly in section, showing transisitors mounted on the heat dissipator of the invention, and

FIG. 13 is a side elevation, partly in section, showing the yheat dissipator in helical form enclosing an electron tube.

As shown in FIGURES 1 to 3 the heat dissipator of the invention lis preferably from heart conductive, deformable wires, or rods, 20 of metal and from heat conductive, deformable sheets or webs 21 also of metal. The wire 20 and sheets 21 may be of copper, aluminum, beryllium or silver, the particular material being selected for the optimum heat dissipating capability of the application. In the specific embodiments illustrated the wire 20 and sheets 21 are of relatively thin copper, the sheet being readily deformable and bendable into desired shapes while still being self supporting and the wire being self supporting, deformable, yieldable and resilient when mounted on a sheet in the short lengths shown.

As shown in FIG. 1, the iirst step of the method of the invention is the forming of the heat conductive wire 20 into plurality of identical wire elements 22, each having at least one pin-like body 23, pin tip 24 and pin base 25. Preferably the elements 22 are formed as looped, or U-shaped staples, by the forming apparatus 26, with each element having a pair of pin bodies, or legs, 23 and 27, a pair of free terminal tips 24 and 28 and a single common base 25.

A plurality of the elements 22 are then temporarily supported with the pin bodies 23 and 27 in parallellism, at spaced distances apart and with the bases 25 all in a common plane. This may conveniently be accomplished by penetrating the tips 24 and 28 through a retainer sheet 29, of paper, or equivalent material, as shown progressively in FIG. 1 until all of the bases are flush with the sheet.

While the elements 22 are so supported, the bases 25 are metallurgically bonded to one face 31 of a sheet 21 to substantially cover the face 31 and create a bristle type surface thereon. As shown in FIG. 2, this step preferably consists of applying a [bonding Vagent 32, which is preferably solder, to the exposed faces of the bases 25, or to the adjacent face 31 of the backing sheet 21, and then heating the solder as by the heating means 33 to metallurgically bond the bases to the face 31 of the sheet 21.

Upon uniting of the elements 22 to the sheet 21, the retainer sheet 29 is then stripped off as indicated in FIG 3. A heat conducting path is thus created between each of the individual, spaced apart tips 24 and 28, along the pin bodies 23 and 27 through the sheet 21 to the opposite face 34 of the sheet.

In FIGURES 4 to 6, the method is similar except that the tips 24 and 28 of the elements 22 are embedded in a retainer sheet 35, for example of bubble-type, polystyrene plastic such as Dow Chemical Companys Styrofoam and while so temporarily supported a backing sheet 21 is applied to the bases 25. In this case the solder 32 is a coating, or layer 36 on the adjacent face of the sheet, the metallurgical bond being accomplished by the heating means 33 as shown in FIG. 6, and the Styrofoam retainer sheet 35 then being stripped.

A sheet, or web 38 of heat dissipator material, constructed `in accordance with the invention, is shown in FIG. 7, in order to illustrate the step of cutting, or slitting the sheet into areas, or blanks, such as 39 and 40 of the desired size to form individual heat dissipators, or sinks.

The metallurgical bonding step may also be accomplished by applying a bonding agent, such as aluminum dip brazing material, to the face 31 0f sheet 21, 0r to the bases 25, and then immersing the assembly in a suitable hot dip to effect the bonding of the parts.

The cutting means 41, which may be disc knives 42 or guillotine knives 43 may be arranged to cut the elongated, narrow strips 39 for bending into a helically wound cylinder or to cut the rectangular blank 40, for use at or bent into a hollow cylinder. It should be noted that the pin bodies 23 and 27 of the elements 22 are not only spaced apart longitudinally from each other and from adjacent elements, but also are spaced apart laterally from adjacent elements so that each pin body and tip is surrounded by an air space into which heat is dissipated.

When the heat dissipator of the inventor is to be shaped, rather than at, the dissipator blanks 39 and 40 are deformed and bent, for example around a mandrel 44 of the selected configuration, as shown in FIG. 8 or they can be wrapped around the heat source itself if desired. The elongated narrow blank 39 is shown wound helically around mandrel 44 to form a hollow cylindrical heat dissipator 45 while the rectangular blank 39 is shown wrapped around the mandrel into a hollow cylindrical dissipator 46 with an axially extending seam, or joint 47.

The heat dissipator, or sink, 46 is shown in FIG. 9 mounted on a typical electron discharge tube 50, carried by a socket 51 affixed to a chassis 52 or other suitable panel, base or support. The dissipator 46 includes the body, or backing, 53 of heat conductive, thin, self supporting material, such as copper, having opposite faces 54 and 55. In this embodiment the plurality of pins such as 56, formed by the pin bodies of the elements 22, project radially inwardly with the free terminal tips 24 and 27 in engagement with the exterior wall 57 ofthe tube envelope 58 and the pin bases 25 metallurgically bonded to the inner face 54.

The envelope supports the dissipator by frictional contact over a multiplicity of minute tip areas, and the pins conduct heat from the envelope to the outer face 55 while dissipating heat into the air spaces 59 between the pins. The seam 47 may be open or closed as desired, but preferably is soldered as at 61. Convection causes heated air to emerge from the open end 62 of the heat sink 46 and cooled air to enter the opposite end 63 and the large surface area of outer face 55 tends to dissipate heat into the air surrounding the heat dissipator.

In FIG. l0, a heat dissipator 65 is shown, similar to heat dissipator 46 except that it is formed into a hollow cylinder on a mandrel of less diameter than the diameter ofthe envelope on which it is to be used. The heat dissipator 65 also includes an integral band 66 along one edge portion having a row of perforations 67 therealong for use in anchoring the dissipator to a chassis or for air circulation purposes. When dissipator 65 is axially slid down over envelope wall 70, the radially, inwardly projecting pins 68 become uniformly angularly disposed `upwardly in an axial direction while still remaining in their 4original radial planes. Fastening clips such as 69 or any other suitable type of clip, are then applied by screws 71 to anchor the dissipator 65 to the chassis 52. Because ofthe yieldability and resiliency of the angularly disposed pins 68, the pins serve the double purpose of conducting heat away from the envelope while serving as a shock mount or impact cushion to protect the envelope and tube.

In FIG. 1l, the heat dissipator 45 is shown as an elongated, narrow strip helically wound, or wrapped around the envelope 58 of an electron tube.

In FIG. 12 a llat heat dissipator 72 is shown, the dissipator 72 having an integral band 73 containing a row of perforations 74 for use in supporting the dissipator in upstanding position. Clips 69 with screws 71 are shown, alternate clips being opposed to each other. One or more transistors 75 and 76 are supported on one .face 77 of the dissipator, by any convenient means, such as by drilling a hole in the body, or backing, 78 and inserting the transistor therein, by a layer 79 of suitable bonding material such as solder or `by suitable attachment screws or bolts.

In FIG. 13 the heat dissipator, or heat sink 80 is in the form of a helically wound narrow strip forming a cylinder, but with the body `81 in engagement with the envelope of the tube 50 and the multiple pin face on the outside for dissipating heat into the surrounding air.

It will `be apparent that while the embodiments shown are preferred, there are many changes in detail which could be made by those skilled in the art without departing from the scope of the invention as defined in the following claims.

I claim:

1. The method for making a heat dissipator comprising the following steps:

(a) positioning and supporting a temporary retainer sheet so that one major surface thereof is entirely unobstructed;

(b) forming a metal Wire into a plurality of heat conductive elements each having a pin base and an integral pin body at right angles to each other;

(c) driving the wire elements in spaced relation into the temporary retainer sheet in a direction normal to a major surface thereof, the wire elements being supported and stabilized by the retainer sheet;

(d) applying a layer of heat conductive metal-containing bonding agent to the pin Abases of the wire elements;

(e) positioning `a metal sheet member against the bonding agent layer;

(f) applying heat to the bonding agent to effect a metallurgical bond between the metal sheet member and the pin bases; and

(g) removing the temporary retainer sheet from the wire element pin bodies.

2. The method for making a heat dissipator comprising the following steps:

(a) positioning and supporting a temporary retainer sheet so that one major surface thereof is entirely unobstructed;

(b) forming a metal wire into a plurality of heat conductive elements each having a pin base and an integral pin body at right angles to each other;

(c) driving the wire elements in spaced'relation into 5 6 the temporary retainer sheet in a direction normal to References Cited a major surface thereof, the wire elements being sup- UNITED STATES PATENTS ported and stabilized by the retainer sheet;

(d) applying a layer of heat conductive metal-containing lbonding agent to a metal sheet member; 5

(e) positioning the metal sheet member so that the 2,722,048 11/1955 Gler 29"157'3 surface thereof carrying the bonding agent layer 2961749 11/1960 Brown et al' H 29-423 X contacts the pin bases of the wire elements;

(f) applying heat to the bonding Aagent to eifect a met- FOREIGN PATENTS allurgica'l bond between the metal sheet member 10 159,624 4/1905 Germany' and the pin bases; and

(g) removing the temporary retainer sheet from the JOHN F CAMPBELL Pr'mary Examm' wire element pin bodies. D. C. REILEY, Assistant Examiner.

2,365,670 12/1944 Wallace. 2,678,808 5/1954 Gier. 

